Multiconduit buoyed underwater line

ABSTRACT

A flexible underwater line has a plurality of conduits layed in a helical configuration about a central core member. The central core member in turn has a group of spokes, extending radially therefrom and each group is disposed at spaced intervals along its length. The conduits are layed between the spokes so that the spokes protrude above the conduits and a ring-buoy is clamped about each group of spokes so that the spokes prevent the buoys from moving axially along the central core member.

United States Patent [72] Inventor George W. Morgan Anaheim, Calif. [21I Appl. No 874,163 [22] Filed Nov. 5, 1969 [45] Patented Aug. 10, I971[73] Assignee North American Rockwell Corporation (54] MULTICONDUITBUOYED UNDERWATER LINE 11 Claims, 4 Drawing Figs. [52] US. Cl 9/8 R,174/ 101.5 [51] Int. Cl 02g 9/12 [50] Field of Search 9/8 R;

[56] References Cited UNITED STATES PATENTS 311,149 1/1885 Stevens138/113 3/1920 Dray 138/103 3,332,093 7/1967 Skinner et al. 9/83,425,453 10/1965 Fuller 138/111 3,489,182 1/1970 Cameron... 9/83,517,110 6/1970 Morgan 9/8 Primary Examiner-Milton Buchler AssistantExaminer-Gregory W. OConnor Attorneys-L. Lee Humphries, Charles F.Dischler and Dominick Nardelli ABSTRACT: A flexible underwater line hasa plurality of conduits layed in a helical configuration about a centralcore member. The central core member in turn has a group of spokes,extending radially therefrom and each group is disposed at spacedintervals along its length. The conduits are layed between the spokes sothat the spokes protrude above the conduits and a ring-buoy is clampedabout each group of spokes so that the spokes prevent the buoys frommoving axially along the central core member.

Patented Aug. 10, 1971 3,597,779

2 Sheets-Sheet 1 INVENTOR. GEORGE W. MORGAN A T TORNE Y Patented Aug.10, 1971 v 3,597,779

2 Sheets-Sheet 2 FIG 4 INVENTOR. GEORGE W. MORGAN A TTORNE' YMULTICONDUIT BUOYEI) UNDERWATER LINE This invention relates tounderwater lines and more particularly to flexible lines which may. forexample, function as risers.

In my U.S. Pat. application, Ser. No. 72l,0l4 filed on Aug. l2, I968,now US. Pat. No. 3,526,086 and assigned to the same assignee as thispatent application there is disclosed an underwater line wherein aplurality of conduits are layed in a helical configuration around acentral core member which is capable of withstanding a relatively hightensile load. Therefore, when the underwater line is used as a riser,the top end of this core member is tied to a buoy to support all weightof the riser. This arrangement produces relatively large stresses in thecore member near the buoy, especially in very long risers. Of course thestress decreases linerally with depth. Therefore, the core member isunderstressed at the lower end making inefficient use of the availablematerial.

Therefore, an object of this invention is to produce a riser whereinefficient use of the material is made.

Another object of this invention is to provide means in a riser toperiodically support the weight thereof to prevent the development ofrelatively large stresses.

These and other objects and features of advantages of the presentinvention will become more apparent from reading the following detaileddescription in conjunction with the accompanying drawings, in which:

FIG. 1 shows a portion of the complete riser incorporating the featuresof this invention;

FIG. 2 shows the central core member before wrapped with conduits andfiller material;

FIG. 3 shows the riser with various items removed to show the novelfeatures thereof; and

FIG. 4 is a section of the riser taken at one of the buoys, and at line4-4.

Referring to the drawings and to FIGS. 2 and 3 in particular, there isshown the preferred embodiment of the novel riser which includes a coremember preferably in the form of a metallic pipe or tube 11. Helicallywound around the tube are a plurality of conduits or metallic tubes 12,for example, eight. Between the tubes 11 and 12 (FIG. 4) is disposedfiller material, for example, plastic threads 13 and 14 of variousdiameters so that substantially all the spacing between the tubes isfilled and the tubes are prevented from rubbing against each otherwhenever the riser flexes due to sea currents. A suitable cover, forexample a plastic sheet 17, is placed around the tubes 12 and plasticthreads 13 and I4 and secured by suitable means. In addition buoys 21are axially spaced along the riser to provide a slight amount ofpositive buoyancy to the riser. Since the buoys have positive buoyancyand tend to rise and since the tubes II and 12 have negative buoyancyand tend to sink, one feature of this invention is to provide means fortransferring the shear forces therebetween.

As shown in FIG. 2, the shear force transferring means includes spokegroups spaced axially along the core member I1. Each group containsspokes 26 that are arranged evenly around a circle to extend radially.The spokes 26 can be, for example, spot welded to the core member 11 forstructural strength. In addition the spokes in one group are preferablyaligned with the respective spokes on each of the other groups. Theconduits I2 lie in the sector formed by two spokes 26 as shown in FIG.4. Since the conduits 12 are helically wound around the core member I],each conduit 12 advances preferably one sector in a clockwise directionas it winds around the core member as shown in FIG. 3. The plasticthreads 13 and 14 preferably twist in the same manner that the conduitstwist. Since the groups 25 are axially spaced along the riser, theplastic sheet 17 preferably extends from one group 25 to the next one.The sheet 17 can be fastened in place by, for example, stitches 18. Asseen in FIG. 3 the spokes 26 have a length so that they protrude beyondthe plastic sheet 17. The buoys 21, which are toroidal in shape, aremade into two similar sections with a semicircular channel-shapedmetallic stitTner 31 disposed on the inner curved edge thereof. Suitablebuoyant material 32 is molded onto the stiffners 31. Therefore when bothbuoy sections are bolted in place as shown in FIG. 4 the ends of thespokes are disposed within the channel-shaped stiffners 31 therebypreventing the buoys 21 from moving axially along the risers.

With the present disclosure in view, modifications thereof would appearto those skilled in the art. Accordingly, the invention is not limitedto the illustrated embodiment but includes all such modifications andvariations within the scope of the invention as defined in the appendedclaims.

What I claim is:

I. A riser comprising:

a core member adapted for extending substantially vertically in theocean,

a plurality of conduits layed along side said core member,

means for bundling said conduits and core member together,

a plurality of spokes extending from said core member and through saidbundling means, and

at least one buoy fixed to said riser and engaging at least one of saidspokes so that said buoy is prevented from moving along said riser.

2. The riser of claim I wherein:

said spokes are disposed in at least one group and lying in a circlearound said core member, and

said buoy is toroidal in shape and made of two similar sections,

both of said sections are clamped around said risers and engage all thespokes in one of said groups.

3. The riser ofclaim 2 wherein:

said groups are spaced along said riser and said conduits lie in thesectors formed by two spokes.

4. The riser of claim 1 wherein:

said conduits are helically wound around said core member,

and

filler material is placed between said conduits and core member toprevent rubbing therebetween when said riser flexes.

5. The riser ofclaim 1 wherein:

said buoy has a channel-shaped stiffener disposed at the inner curvedperiphery of each of said sections, and

the ends of said spokes are disposed within said channelshaped stiffenerwhen said buoy is clamped to said riser.

6. The riser of claim 2 wherein:

said conduits are helically wound around said core member,

and

filler material is placed between said conduits and core member toprevent rubbing therebetween when said riser flexes.

7. The riser of claim 3 wherein:

said conduits are helically wound around said core member,

and

filler material is placed between said conduits and core member toprevent rubbing therebetween when said riser flexes.

8. The riser of claim 3 wherein:

said buoy has a channel-shaped stiffener disposed at the inner curvedperiphery of each of said sections, and

the ends of said spokes are disposed within said channelshaped stiffenerwhen said buoy is clamped to said riser.

9. The riser of claim 4 wherein said buoy has a channel-shaped stiffenerdisposed at the inner curved periphery of each of said sections, and

the ends of said spokes are disposed within said channelshaped stiffenerwhen said buoy is clamped to said riser.

10. The riser ofclaim 6 wherein.

said buoy has a channel-shaped stiffener disposed at the inner curvedperiphery of each of said sections, and

the ends of said spokes are disposed within said channelshaped stiffenerwhen said buoy is clamped to said riser.

11. The riser of claim 7 wherein said buoy has a channelshaped stiffenerdisposed at the inner curved periphery of each of said sections, and 75the ends Ffsaid spokes are disposed wifliihiaid cha hnel shapedstiffener when said buoy is clamped to said riser.

1. A riser comprising: a core member adapted for extending substantiallyvertically in the ocean, a plurality of conduits layed along side saidcore member, means for bundling said conduits and core member together,a plurality of spokes extending from said core member and through saidbundling means, and at least one buoy fixed to said riser and engagingat least one of said spokes so that said buoy is prevented from movingalong said riser.
 2. The riser of claim 1 wherein: said spokes aredisposed in at least one group and lying in a circle around said coremember, and said buoy is toroidal in shape and made of two similarsections, both of said sections are clamped around said risers andengage all the spokes in one of said groups.
 3. The riser of claim 2wherein: said groups are spaced along said riser and said conduits liein the sectors formed by two spokes.
 4. The riser of claim 1 wherein:said conduits are helically wound around said core member, and fillermaterial is placed between said conduits and core member to preventrubbing therebetween when said riser flexes.
 5. The riser of claim 2wherein: said buoy has a channel-shaped stiffener disposed at the innercurved periphery of each of said sections, and the ends of said spokesare disposed within said channel-shaped stiffener when said buoy isclamped to said riser.
 6. The riser of claim 2 wherein: said conduitsare helically wound around said core member, and filler material isplaced between said conduits and core member to prevent rubbingtherebetween when said riser flexes.
 7. The riser of claim 3 wherein:said conduits are helically wound around said core member, and fillermaterial is placed between said conduits and core member to preventrubbing therebetween when said riser flexes.
 8. The riser of claim 3wherein: said buoy has a channel-shaped stiffener disposed at the innercurved periphery of each of said sections, and the ends of said spokesare Disposed within said channel-shaped stiffener when said buoy isclamped to said riser.
 9. The riser of claim 4 wherein: said buoy has achannel-shaped stiffener disposed at the inner curved periphery of eachof said sections, and the ends of said spokes are disposed within saidchannel-shaped stiffener when said buoy is clamped to said riser. 10.The riser of claim 6 wherein: said buoy has a channel-shaped stiffenerdisposed at the inner curved periphery of each of said sections, and theends of said spokes are disposed within said channel-shaped stiffenerwhen said buoy is clamped to said riser.
 11. The riser of claim 7wherein: said buoy has a channel-shaped stiffener disposed at the innercurved periphery of each of said sections, and the ends of said spokesare disposed within said channel-shaped stiffener when said buoy isclamped to said riser.